Tow slicing apparatus



Nov. 18, 1969 A. ABDEL-MONIEM GORRAFA ,478,

TOW SLICING APPARATUS Filed April 9, 1968 2 Sheets-Sheet 1 INVENTOR ADLY ABDEL- MONIEM GORRAFA BY A owwwc L Z ATTORNEY N 3, 1969 A. ABDEL-MONIEM GORRAFA 3,478,392

TOW SLICING APPARATUS Filed April 9', 1968 v 2 Sheets-Sheet 2 INVENTOR ADLY ABDEL- MONIEM GORRAFA ATTORNEY Unit d t s P t n .U.s. c1. 19-.62 v2 Claims I 7 ABSTRACT OF THE DISCLOSURE Background of the invention This invention relates to the production of textile material, and more particularly, to an apparatus for cutting continuous textile filaments to short lengths. It 'is 'known to cut a tow of synthetic organic continuous filaments to staple, pick the staple and then card it to a web which is drafted and twisted to roving and yarn Recent attemtps to by-pass the expensive picking and carding steps have been highly successful. These methods involve use of a converter, such as the Pacific converter, which cuts continuous filament tows to a staple web and converts it directly to sliver. These converters have been successfully used with the worsted system of drafting and spinning to a yarn. Unfortunately, the converters' are totally inadequate-when used in connection with the cotton system. The recent development of opened tow, i.'e., tow having a minimum of caterpillars or married fibers, solved part of the problem, but the resulting yarn was still not completely satisfactory. Reasonsfor this have been traced to crushed and matted tipsof the staple fibers which invariably occur as a result "of the type of cutter commonly used in the converter. Some prior artcutters, not used in converters, produce clean-cut staple in the form of tufts which must be picked and carded to form a continuous web. The art is not aware of a converter which, when fed with opened tow, produces a continuous web of clean-cut staple fibers having individualized and separated tips, which needs no picking or carding but may be drafted directly to sliver,

roving and yarn, even on the cotton system, and such -'is provided by the present invention.

Summary of the invention This invention provides an apparatus for cutting a tow sheet of continuous synthetic fibers to a continuous web, comprising tow feed means, a pair of coacting, counter-rotating, axially coplanar,- cylindrical rollers .which are mounted to rotate about their axes and which are spaced apart insubstantial parallelism to allow passage of tow therebetween, and web take-up means. One

'of the rollers has at least one helically disposed sharp blade on its surface and the other has at least one groove disposed helically and of opposite hand in its surface.

-vided to rotate said rollers and to drive the feed and web take-up means.

Patented Nov. 18, 1969 ice Brief description of drawings FIGURE 1 is a perspective view of one embodiment of the cutter of the present invention.

FIG. 2 is a schematic elevational view of the coacting rollers of FIG. 1.

FIG. 3 is a schematic side elevation of an embodiment of the present invention including forwarding and take up means.

FIG. 4 is a schematic side elevation of another embodiment of this invention.

' Detailed description of the illustrated embodiments FIG. 1 shows tow 10 pasing between counter-rotating axially coplanar roller 11 and 12, which are mounted, to be rotatable about their respective axes in the direction of the arrows, on rigid supports 20 and 20. Rollers 1 1 and 12 are driven by motor 13 through gears 14 and 15. Roller 11 has two equispaced right-hand helical blades 17 and 17 on its peripheral surface and roller 12 has three equispaced left-hand helical grooves 18, 18' and 18" on its peripheral surface. Tow 10 passes between rollers 11 and 12 and is converted to a web 19 of staple 'fibers with individualized tips by the slicing'action of the blades 17 and 17' in their mating grooves. As will be explained below, the peripheral speed of the blades is greater than the feed speed of the tow. Web-cut angle 0 is the acute angle between the cut lines 16 and the direction of movement of the web, as shown.

FIG. 2 illustrates what is meant by non-contacting mesh with regard to blades 17 and 17 in grooves 18, 18 and 18". Although no part of roller 11 or its associated blades touch roller 12, it is necessary to reduce the distance between the roller axes so that the blade tips extend into the associated grooves of roller 12 at the tow-passage space. Preferably, the blades extend about 0.03 to 0.25 inch (0.8 to 6.4 mm.) into the grooves. It is necessary that each blade have an associated groove at the tow-passage space. The distance, or gap G, between roller surfaces in the tow-passage space must be at least equal to the thickness of the fiber sheet as it passes be.- tween the rollers; otherwise, frictional contact will generate objectionable heat and fusing of-the fiber. The width of the grooves 18, 18', and 18" must be greater than the blade tip thickness and must allow for the oblique disposition of the blade in the groove in order to preclude contact of blades with the walls of the grooves. The depth of the grooves must also be slightly larger than the blade extension therein to preclude contact with the sharp blade edge.

This particular relationship between the blade and the groove not only permits clean slicing of tow without crushing and matting but also permits the blades to riflle the ends of the cut staple to provide individualized separated tips.

FIG. 3 shows a preferred method for feeding and delivering the fibrous sheet in the present process. Endless feed and take-up aprons 21, 21', 22 and 22' travel. around their respective rollers 23-26 which rotate in the directions of the arrows shown. Tow 10 passes in'the nip of feed aprons 21 and 21' and then passes through the towpassage space between rollers 11 and 12' and is sliced at point A to staple web 19 therein. Just following rollers 11 and 12 the web is withdrawn through the nip B of take-up aprons 22 and 22' andthen passes to an appropriate .teX- tile operation such as sliver formation or drafting preliminary to yarn manufacture. The distance from A .to-B' should be the minimum practical and must be shorter than the staple length being produced; Take-up aprons 22 and 22' are run at a speed at least equal to the speed of the feed aprons 21 and 21. The resultant tensioning draft should be adjusted in proportion to the degree of crimp recovery in the material, i.e., the extent to which a pre-crirnped but tensioned fiber retracts upon slicing it and its relation to distance AB.

In an alternate embodiment shown in FIG. 4, the grooved roller 12 may be replaced by a driven endless flexible belt 27, which travels around rollers 28, 29. The belt has diagonal grooves 30 in its outer surface to accommodate blades 17 of roller 11 as previously described. For the purpose of calculating the belt specifications according to the conditions set forth below for a grooved roller, the belt is imagined to assume a perfectly cylindrical form on which the helical grooves are constructed. Once fully defined, the cylindrical form of the belt is no longer necessary and the belt is fabricated and installed in the apparatus by conventional techniques.

The following definitions will contribute to an understanding of the present invention. In the letters referring to roller description, capital letters refer to the particular variable on the bladed roller while lower case letters refer to the paticular element of the grooved roller.

f=tow feed speed [yards/min. (m./min.)]

l =maximum staple length [inches (cm.)], which is achievable with a specific apparatus =web cut angle (degrees) D=helix diameter [inches (cm.)], corresponding to the outside diameter of the helical blade or groove N=number of helix starts on the roller (blades or grooves) Q=helix lead [inches (cm.)] which is the axial advance of a helix for each complete turn, e.g., since there are two blades on roller 11 of FIG. 2, Q" is as shown R=roller rotational speed [revolutions per minute] S=roller peripheral speed [yards/ min. (m./min.)]

i=any integer (a constant for a specific embodiment) A: slice ratio which is the ratio of To achieve the benefit of the present invention it is important that A be greater than 1. Preferably, A is in the range of 1.1 to 6.

In the practice of this invention the following relationships must be satisfied:

(1) The helices on one roller must be of opposite hand to the helices on the other coacting roller. In FIGS. 1 and 2 the helical blades of the cutter roller are of righthand helix and the helical grooves on the grooved roller are of left-hand helix. However, it is obvious that the blades of the cutter roller could be of left-hand helix, in which case the associated grooves of the coacting grooved roller must be of right-hand helix.

(2) R/r=n/iN (3) d=l (n)1ri (4) D=l AN/1r (5) q=nl tan e/i (6) Q=Nl tan 0 In setting up the apparatus for producing certain web characteristics, the starting point in the necessary calculations stated herein is the l which is the maximum staple length that the particular apparatus will be requlred to produce. Concurrent with the choice of l a specific 0 is chosen which will make the web suitable for handling in the desired subsequent operations such as sliver formation. Preferably, 0 is in the range of 5 to 45. Knowing l and 0, integers i, N and n are selected based on economy of manufacture of the rollers. A slice ratio A is then selected at a value compatible with smooth and clean slicing of the sheet material to be fed into the apparatus. These variables are then substituted in the defined equations above the yield the specifications of the apparatus.

It should be noted that the magnitude of integers N and n will directly influence the diameters of the rollers required to meet the conditions for l A and i. Accordingly, the choice of N and it depends on the specific 4 use intended, space limitations, strength of material from which the rollers are fabricated, and other practical considerations. Integer i may be physically perceived as being the frequency of blade-in-groove engagements occurring along the gap G shown in FIG. 2. Thus, when i is 2, a blade will engage with each second groove along the gap G and when i is 5, a blade will engage with each fifth groove along the gap G. The value of integer i will not alfect the bladed roller specifications, but it will affect diameter d and helix lead q of the grooved roller in an inverse relationship. Unless particularly desired to make the grooved roller multifunctional as will be explained below, it willbe appreciated that integers i and It should have a highest common factor of only 1; e.g., 2 and 3 instead of 4 and 6, in order to avoid costly fabrication of unnecessary grooves.

The surface speed s of the grooved roller is an independent variable; e.g., it can be set at any practical value without influencing interaction between the two rollers. Tow feed speed f is also an independent variable up to the limit 6'. When process settings are such that f is equal to s, the staple length produced is l It was found that the staple length produced is directly proportional to the magnitude of f relative to s. Thus, when f is only, say, one-half of s, the staple length produced is only onehalf of l Similarly, when is only its the staple length produced is only al (5 being less than 1.0). It is ap parent that such ease in making changes in staple length without resorting to costly prior art methods involving changing the cutter roller is a great advantage over the art. The web-cut angle 0 is the angle obtained when producing staple length l Upon changing the staple length to a new length, say, fil the corresponding new webcut angle is increased to are tan [tan 0/6] degrees.

Slice-ratio A, as used herein, obtains only when staple length is l When changes in staple length are made by changing feed speed f, the corresponding slice ratio (S/f) will obviously be greater than A.

Since a change in staple length will be accompanied by a change in web-cut angle as described above, it is obvious that in order to produce two distinctly different staple products, say, l and l' each with the same web-cut angle 0, each product will require its own matched pair of co-acting rollers. If i is the integer used in the specifications of the first apparatus for producing the product with staple length l and i is the integer used in the specifications of the second apparatus for producing the product with staple length l' it was surprising to find that when the ratio /i is equal to the ratio l /i', the grooved roller of the first apparatus is also suitable for the second apparatus after simple adjustment of the rotational speed of the rollers. Thus, the same grooved roller is made multifunctional with two machines by simply selecting i and i to make the indicated ratios equal. Those skilled in the art will be able to extend the interchangeability advantage of this invention, e.g., in making the same bladed roller multifunctional with different grooved rollers under certain conditions of process and product specifications. The economic advantage due to roller interchangeability is readily recognized.

The coacting rollers are preferably made of steel and the blades are preferably of hardened steel to withstand prolonged operation with infrequent sharpening.

If it is desired, an in situ honing device may be added to the apparatus to maintain a sharp cutting edge on the blades. The honing device may be in the form of a helically grooved grinding roller in contacting engagement with the blades of the cutter roller to provide continuous honing. The helical grooves of the grinding roller are made of the same hand as the helical blades of the cutter if both rolls are to rotate in the same direction; e.g., clockwise. Preferably, the helices of the grinding roller are of opposite hand to that of the blades and the rollers rotate in opposite directions. To design the in situ honing system, a number of helical starts g is selected for the grinding roller and an integer k is also chosen. The helix lead and rotational speed for the grinding roller are specified as:

Grinding roller lead=gQ/Nk [inches (cm.)] Grinding roller speed=RNK/g [revs/min] The diameter of the grinding roll is an independent variable and can be of any size. Preferably a diameter is chosen such that the corresponding peripheral speed of the grinding roller is adequate to yield smooth and effective blade sharpening. The role of integer k is the same as that of integer i, mentioned above; namely, it physically shows the frequency of blade-in-groove matings taking place along the contact between the two rollers.

EXAMPLE 900,000-denier tow comprising filaments of conventional poly(ethylene terephthalate) of 1.5 denier per filament is fed, under suflicient tension to straighten out the crimp, to an apparatus similar to that of FIG. 1 including the feed and take-up aprons of FIG. 3. The speed of the feed aprons equals s and the speed of the take-up aprons is 1.25 f. The following specifications which satisfy the above requisite mathematical relationships are used.

i=2; A=2.03; l =3 inches (7.62 cm.); 0=arc tan (about 24 degrees); N=2; D=3.875 inches (9.843 cm.); Q=2-2/3 inches (6.773 cm.) R=37.725 revolutions per minute; S=l2.75 yards per minute (11.66 m./min.); n=3; d=1.432 inches (3.638 cm.); q=2 inches (5.08 cm.); r=50.3 revolutions per minute; c=6.28 yards per minute (5.74 m./min.); f=6.28 yards per minute (5.74 m./min.). Helical grooving is 0.1 inch (0.254 cm.) wide and 0.062 inch (0.158 cm.) deep.

The Web so produced exhibits no crushed or matted tips and the fiber ends are individualized and cleanly cut.

It is practical to make continuous webs of fibers of any staple length greater than about 1.5 inches (3.8 cm.) on the new apparatus. Feed speeds f of from 2. to 200 yds./min. (1.83 to 183 m./min.) may be easily reached.

If the staple web is to be made directly to a sliver for processing on the cotton system of drafting and spinning, it is preferable to use an opened starting tow, i.e., one with few caterpillars or married fibers crimped in phase. A variable cut staple diagram may be obtained by simply zig-zagging the feed tow from one side of the apparatus to the other.

The apparatus of the present invention is an advance in tow-cutting art. Tow can be cut with the new apparatus to staple with clean-cut, non-matted individualized ends. The cutting operation converts the tow to a continuous web for readily producing a sliver capable of uniform drafting even on the cotton system.

Webs produced on the new apparatus may also be used directly for filling material such as mattresses and chair cushions.

A great advantage in the new apparatus is the ease of changing staple length by merely changing tow feed speed In many apparatuses of the art, to change staple length the cutter roller itself has to be changed. Such disadvantage is obviated by use of the apparatus of this invention.

Another utility of this invention is to produce, by a slicing action, diagonally cut strips of sheet material such as fabrics, webs, laminates, films, paper, etc. These strips are used in different applications such as tire manufacturing, core tubes and soft-drink straws. The width of such strips, measured along the flow direction, is obviously the same as the staple length produced with a continuous filament tow feed.

Since many different embodiments of the invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the following claims.

What is claimed is:

1. In a machine for converting continuous filament tows to a web of staple fibers that includes, a tow forwarding means, a means for cutting the tow into staple fibers, and a web take-up means positioned downstream from said forwarding means, an improved cutting apparatus comprising:

(a) a support positioned between said tow forwarding means and said web take-up means;

(b) a pair of cylindrical rollers rotatably mounted in substantially spaced parallel relationship in said support to allow passage of tow therebetween, one of said rollers having at least one helically disposed cutting blade on its peripheral surface, the other of said rollers having at least one helically disposed groove in its peripheral surface, said blade being of opposite hand with respect to and in non-contacting mesh with said groove; and

(c) means coupled to said rolls for rotating them in opposite directions at different speeds.

2. An apparatus for converting a sheet of continuous synthetic fibers to a continuous web of cut fibers, said apparatus comprising:

(a) means for forwarding the sheet in a linear path;

(b) an endless driven belt positioned downstream of said forwarding means, said belt having an outer surface beneath said sheet and in contact therewith,

(c) a cylindrical roller rotatably mounted above said outer surface, said roller having a peripheral surface spaced from and in substantial parallelism with said outer surface, there being at least one cutting blade helically disposed on said peripheral surface, said belt having diagonal grooves in its outer surface, said blade being of opposite hand with respect to and extending partially into at least one of said grooves, there being clearance maintained between said groove and said blade during relative movement therebetween; and

(d) means coupled with said roller for rotation thereof, the peripheral surface speed of said roller being greater than and in the direction of said belt.

References Cited UNITED STATES PATENTS 2,172,359 9/1939 Campbell 83-342 3,304,821 2/ 1967 Matino et a1 83913 XR FOREIGN PATENTS 470,543 6/ 1914- France.

DORSEY NEWTON, Primary Examiner US. 01. x.R. 83-680, 913

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 }{f( 39 Dated November 18, 1969 Invenro1-(S)Adly Abdel-Moniem Gorrafa It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 51, that portion of the equation reading (n)7 i" should read (n)/ i Column 5, line 5, that portion of the equation reading "RNK/g" should read RNk/g line 32, that portion of the equation reading '0 6.28" should read SIGNED AN'D SEALED APR281970 (SEAL) Attest:

Edward M. Fletcher, Ir. Attesting Officer WILLIAM 'suflugmt' Commiss loner of Patants 

